Prophylactic Acetaminophen Reduces Immunogenicity of Childhood Vaccines

Children given acetaminophen with vaccinations have lower rates of fever in response, but the vaccinations produce a lower immunogenicity, reports a Lancet study.
Researchers, including some from the sponsoring vaccine manufacturer, followed over 400 infants receiving primary and booster immunizations. Half received acetaminophen via suppository in three doses over the first 24 hours after vaccination, and half received no prophylaxis.
The percentage of children with a temperature of 38 degrees C or higher was significantly lower in the acetaminophen group by some 40% to 50% both at primary and booster immunizations. However, vaccine immunogenicity was lower in the acetaminophen group — significantly so for some antigens, e.g., all 10 pneumococcal serotypes after the primary immunization. The authors hypothesize that the effect could result from acetaminophen's preventing inflammation.
Over 95% of all children had seroprotective antibody levels, but researchers argue that antipyretics "should ... no longer be routinely recommended" with vaccination. Editorialists agree, calling the case "compelling."